I’ve been playing guitar for quite a while, but today is the first time I’ve ever seen these particular wonderful monstrosities. Above is the “WTF24” TWENTY-FOUR STRING guitar. It seems kinda silly to call it a ‘bass’ guitar specifically. I couldn’t dig up any specs, but this thing must have a range of at least 5-6 octaves, which is 60 or more keys on a piano.
Here’s another megaguitar, but with ‘merely’ 10 strings. When I first saw the thumbnail I assumed it was a joke—but it’s not, and it sounds really amazing:
Here’s a handy instrument range chart: